RESEARCHERS at the Centre for Crop and Disease Management (CCDM) are working to mine the germplasm of wild chickpeas and cross breed them with Australian domestic varieties, with the ultimate goal of making the pulse a more profitable, better yielding option as a break crop for Aussie growers.
The research being undertaken by CCDM is part of an international, multi-pronged approach that is looking to expand the genetic diversity of the world's chickpea varieties, by taking the best traits of wild species and crossing them with domesticated varieties to create more disease resistant options and improve desirable agronomic traits.
CCDM pulse researcher Lars Kamphuis said chickpea varieties around the globe have a very narrow genetic base which means very limited genetic diversity.
"We now know that domesticated varieties have experienced a 95 per cent loss in diversity compared to their wild ancestors, so our job as researchers is to bring that diversity back to make lines stronger and more disease-resistant," Dr Kamphuis said.
"The wild chickpeas we're drawing on not only offer tremendous genetic diversity but have also adapted to variable geography and conditions over thousands of years so we can learn so much about their robustness as a result of their evolution."
The wider project started in 2013 when the Grains Research and Development Corporation (GRDC) invested in a mission to a site in south-east Turkey which remains to date one of the worlds' richest zones of wild chickpea species.
A collaboration was led by CSIRO researcher Jens Berger who spent four years searching for, tagging and collecting seed samples from often difficult-to-find wild populations.
The collections were then shared among an international collaboration of researchers each with a job to do to better understand how the wild past could be used for a more sustainable future.
As part of the multi-layered GRDC-invested project, CCDM's research focuses on ascochyta blight (AB), a crippling disease of chickpea, as well as sclerotinia stem rot (SSR).
Dr Kamphuis said the team evaluated a collection of about 200 wild lines and identified five genetic lines that showed good resistance to a range of AB disease-causing isolates, including some very aggressive ones.
"With those five highly resistant lines we then made crosses back into two common domesticated varieties to try and bring those resistance traits in," Dr Kamphuis said.
"By doing this we are aiming to get a better understanding of which areas in the wild chickpea genetic information gives rise to the greater levels of disease resistance."
Ascochyta blight was responsible for almost wiping out Western Australia's chickpea production, leaving much of the State's potential crop area under-utilised.
However the work being done is helping to develop pre-breeding material that can be used to revitalise potential expansion of cropping zones and give growers a valuable pulse crop in their rotation system.
Dr Kamphuis said the research involves both molecular lab-based work and two years of field trials across Australia in 2019 and 2020.
"Chickpea lines from this work will be selected in conjunction with breeders, with the aim of getting viable, more diverse material into breeding programs as early as next year," he said.
In 2019, 60,000 lines derived from crosses between wild chickpea plants and Australian varieties were planted into three trial sites across Australia, including Breeza in New South Wales, a field trial area at Shenton Park and at Mingenew where CCDM worked closely with the Mingenew-Irwin Group.
Working with chickpea breeder Kristy Hobson in Breeza, the CCDM team evaluated results from last year's trials to determine best options to go into the ground this year.
In 2020, the Mingenew and Breeza trials are being repeated, with Wagga Wagga and a new site in Cunderdin in WA also added in and CCDM research fellow Silke Jacques guiding the trials.
"Each site provides a snapshot of how the wild chickpea lines fare in different soil types and environments," Ms Jacques said.
"In WA in particular we are looking at the red loamy soils of Mingenew and the more sandy, clay soils of Cunderdin with the ultimate aim of hoping to offer opportunities to open up more of the State to chickpea production in the future."
The research team spent weeks at the start of this year threshing the plants, collecting thousands of seeds and measuring them for seed shape, colour, texture, size and yield, from this, 443 genetic lines were selected for further testing this season.
Following the field trials the next step is to head into the lab for further molecular testing of those populations that are showing best potential for further development.
Dr Kamphuis said they're looking into a particular population that is showing good traits that control disease resistance.
"Our plan will be to use a molecular technique to create lots of little flags in the plant genomes from that population and correlate those with the plant's phenotype, including AB resistance, physical characteristics such as growth habit and height, flowering time, time-to-pod, vigour and seed size, shape and colour," he said.
"With the aim being to try and identify which areas of the genome and which genes that define those areas might be responsible for that particular resistance trait.
The idea is that those 'flags' can be passed on to the breeder to further use in their breeding program to select for those desirable traits.
From there, further crosses with different sources that have different traits can be made to try and help develop future breeding varieties that contain as many of the positive traits as possible.
Dr Kamphuis said part of the research is also looking at how pre-breeding may also be used to eliminate the less desirable traits of the wild chickpea such as its ground cover-style growth and its irregular seed style.
"Ideally chickpea varieties suited to Australian conditions that we are looking for have good height growth, smooth seeds, early flowering and early maturity to escape late-season drought and most of all good resistance to AB," he said.
"At the end of the day it's about future industry growth, finding the right varieties to not only resurrect the viability of chickpea as a profitable crop in Australia across a broader area of Australian grain production and to expand its appeal as a worthwhile rotation option."
To find out more about the wild chickpea work, tune into the GRDC podcast featuring Dr Kamphuis at grdc.com.au/podcasts